Mixing apparatus for pulverulent or granular material and improved method for mixing such material

ABSTRACT

A method of, and apparatus for, admixing at least two fluent material components, especially pulverulent or granular materials, wherein the internal compartment of a material receiving container is sub-divided by partition walls into two storage compartments having a volume ratio essentially corresponding to the desired mixing ratio of the material components. Each of the storage compartments is filled with the material components which are to be admixed. The filled material components are withdrawn from the storage compartments into a collecting zone in a ratio corresponding to the desired mixing ratio of such material components. Means serve to generate a negative pressure condition at the region of the collected material components withdrawn from said storage compartments, by means of which there is produced a material conveying fluid medium stream over the surface of the collected material components to remove therefrom the components of the collected material in a ratio corresponding to the desired mixing ratio. The thus withdrawn material components to are then transported by the conveying fluid medium stream to a consumer while admixing such material components with one another during movement to such consumer.

United States Patent Weber [75] Inventor: Alwin Rolf Weber, 861 l Bertschikon, Switzerland [73] Assignee: A. R. Weber AG, Zug, Switzerland [22] Filed: Nov. 12, 1971 [21] Appl. N0.: 198,253

[30] Foreign Application Priority Data Nov. 17, 1970 Switzerland ..17001/70 [52] US. Cl ..259/4, 259/36 [51] Int. Cl. ..B0li 13/02 [58] Field of Search ..259/2, 4,18,36, 151, 147

[56] References Cited UNITED STATES PATENTS 2,884,230 4/1959 Pyle ..259/4 3,179,378 4/1965 Zenz ..259/4 3,490,655 l/l970 Ledgett ..259/36 3,647,188 3/1972 Solt ..259/4 Primary Examiner-Robert W. Jenkins AnorneyWerner W. Kleeman [57] ABSTRACT A method of, and apparatus for, admixing at least two fluent material components, especially pulverulent or granular materials, wherein the internal compartment of a material receiving container is sub-divided by partition walls into two storage compartments having a volume ratio essentially corresponding to the desired mixing ratio of the material components. Each of the storage compartments is filled with the material components which are to be admixed. The filled material components are withdrawn from the storage compartments into a collecting zone in a ratio corresponding to the desired mixing ratio of such material components. Means serve to generate a negative pressure condition at the region of the collected material components withdrawn from said storage compartments, by means of which there is produced a material conveying fluid medium stream over the surface of the collected material components to remove therefrom the components of the collected material in a ratio corresponding to the desired mixing ratio. The thus withdrawn material components to are then transported by the conveying fluid medium stream to a consumer while admixing such material components with one another during movement to such consumer.

15 Claims, 2 Drawing Figures MIXING APPARATUS FOR PULVERULENT OR GRANULAR MATERIAL AND IMPROVED METHOD FOR MIXING SUCH MATERIAL BACKGROUND OF THE INVENTION The present invention relates to a new and improved mixing apparatus for pulverulent or granular material and also concerns a new and improved method for the admixing of such materials.

Equipment for mixing granular material, especially plastic granulates, have been known to the art for quite some time. With the heretofore known state-of-the-art equipment suitable for this purpose smaller or larger quantities of the materials to be admixed are pre-mixed and stored in suitable containers until use. However, if the components of such mixtures possess different specific weights, then, storage thereof leads to an at least partial unmixing i.e., separation of the components. Therefore, apparatus has been provided by means of which such unmixing or material reseparation can be prevented in that the pre-mixed quantities of material within the storage container are continuously agitated or maintained in a circulatory movement. Yet, such type apparatus is relatively expensive to acquire and equally so in operation.

SUMMARY OF THE INVENTION Hence, from what has been stated above it will be seen that there is still present a real need in the art for an improved construction of mixing apparatus for pulverulent or granular material which is not associated with the aforementioned drawbacks and limitations of the prior art equipment. Thus a primary object of the present invention is to provide a novel mixing apparatus for pulverulent or granular material which is not associated with the aforementioned drawbacks and limitations and effectively and reliably fulfills the existing need in the art.

Still a further significant object of the present invention relates to a novel apparatus for the admixing of pulverulent or granularmaterials in an extremely efficient and economical manner while avoiding any separation of the components.

Yet a further significant object of the present invention relates to the provision of a novel construction of mixing apparatus for pulverulent or granular materials wherein the components of the mixture are reliably admixed in a desired ratio without any danger of reseparation of the material components.

A further significant object of the present invention relates to a novel method of admixing together pulverulent or granular materials in an extremely efficient and reliable fashion, while safeguarding against reseparation of the admixed components.

Now in order to implement these and still further objects of the present invention, which will become more readily apparent as the description proceeds, the inventive mixing apparatus for fluent materials, especially pulverulent or granular materials, is manifested by the features that the mixing apparatus incorporates an essentially horizontally extending annular or ring-shaped compartment which possesses a cross-sectional configuration which tapers or narrows in the fall direction of the material and merges with an annular or ringshaped gap. The ring-shaped compartment is sub-divided in the peripheral direction thereof into at least two storage chambers or compartments. A collecting compartment is arranged beneath the ring-shaped compartment and is in flow communication with both storage compartments via the ring-shaped gap. There is provided a mixed material conduit which is arranged to ascend out of the collecting compartment and there is also provided a ring-shaped inlet opening for a carrier or transport medium which is disposed within and at the neighborhood of the ring-shaped gap.

As already indicated above a further aspect of this invention is concerned with a novel method of mixing pulverulent or granular materials in a manner preventing separation of the material components. To this end, a container for the different material components is selectively sub-divided into separate storage compartments for the individual materials to be admixed, the volume of these storage compartments corresponding to the mixing ratio of the materials. The materials to be admixed are then introduced into the storage compartments and permitted to flow into a collecting zone in a ratio corresponding to the desired mixing ratio for the material components. There is then generated a negative pressure at the region of the collecting zone which produces a carrier or transport medium, preferably from the surrounding atmosphere, which then is drawn over the surface of the material components which are in the collecting zone. This transport medium serves to entrainably remove from the collecting compartment individual material components in a ratio corresponding to the desired mixing ratio. The transport medium then conveys the material components towards a consumer or load and on its way to this consumer the turbulent action of the conveying or transport air serves to finally admix the components in the desired mixing ratio with one another.

From what has been explained above it will be seen that the objectives of this invention are uniquely realized in that the components of the mixture are maintained in a separate condition in the storage compartments until the mixture is required by the consumer.

The admixing of both material components only then takes place when such are acted upon by the conveying or transport medium which ensures for the delivery of the material components to the consumer through the agency of the mixed material conduit. The transfer of the components in a certain mixing ratio to the transport medium occurs in that, in accordance with the cross-section of the ring-shaped gap sections associated with the storage compartments a proportionate quantity of each of the material components is continuously permitted to flow into the collecting zone or compartment. During such time as the material components are permitted to be guided under the influenceof the force of gravity towards the annular or ring-shaped gap the conveying action through the ring-shaped gap preferably also occurs under the action of the negative pressure which prevails at the neighboring collecting compartment. This negative pressure is present owing to the fact that the mixed material conduit is connected at the side of the consumer to a negative pressure source.

BRIEF DESCRIPTION OF THE DRAWING The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawing wherein:

FIG. 1 is a schematic axial sectional view of a preferred embodiment of inventive mixing apparatus; and

FIG. 2 is a plan view of the mixing apparatus depicted in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the drawing, the exemplary inventive embodiment of mixing apparatus for the admixing of fluent, especially pulverulent or granular materials will be seen to comprise a rotationally symmetrical vessel or container 2 possessing an upstanding or vertical axis. This container 2 will be seen to downwardly taper or converge in a cone-shaped vessel configuration and is bounded by an outer or external wall 4. In other words, the container 2 is in the form of an inverted cone, the jacket surface of which is defined by the external wall 4.

The upper end i.e., the base of the cone-shaped container or vessel 2 is open and the lower end or apex of this cone-shaped container 2 is closed by the external or outer wall 4. Container 2 is supported upon, for instance, three supporting legs or supports 34 which are connected in any suitable manner with the outer wall 4 thereof. A body member or cylinder 24 is situated coaxially with respect to the vertical axis of the container or vessel 2 as well as a tube 16 arranged coaxially within the cylinder 24 serves to subdivide the internal compartment of the container 2 into an annular or ringshaped compartment 6 and an air chute or shaft 30. The ring-shaped compartment 6 is bounded by the outside surface or wall of the cylinder 24 and the outer wall 4, while the inner surface of the cylinder 24 and the outer surface of the tube or pipe 16 delimit the air shaft or chute 30.

The tube 16 is a component of a mixed material conduit arrangement 18. Such is connected through the agency of a suitable consumer or load 26 with the suction side of a conventional blower or ventilator 28. The tube 16 and the cylinder 24 are attached through the agency of four radially extending struts 36 with the outer wall 4 of the container 2, these struts 36 being arranged approximately at the height of the upper edge of such container. An annular or ring-shaped. gap 8, formed between the lower edge of the cylinder body or cylinder 24 and the outer wall 4, operatively communicates the annular or ring-shaped compartment 6 with the lower end of the, air shaft 30 as well as with a col lecting compartment 14 disposed beneath such air shaft.

The inlet opening for the conveying or transport medium is designated by reference character 32, this conveying medium departing'from the air shaft 30 substantially at the height of the ring-shaped gap 8 and at that location entering the collecting compartment 14. The inlet opening 32 possesses a substantially ringshaped configuration and is defined by the lower end of the cylinder 24 and the tube 16.

According to an important aspect of the apparatus construction of this development the annular or ringshaped compartment 6 is sub-divided into plural storage compartments, here two storage compartments or chambers 10 and 12 by means of two radially extending partition or separation walls 20 and 22. One of the partition walls, such as the partition wall 22 is displaceably mounted by means of a carriage arrangement 40 at the cylinder 24 for movement in the circumferential or peripheral direction, this carriage 40 operably engaging the upper and lower edges of cylinder 24 to permit such circumferential displacement of the movable partition wall 22. Mechanism is also provided for fixing the movable partition wall 22 in its desired circumferential position with respect to the other partition wall 20, and such mechanism may comprise, for instance, a suitable fixing or clamping screw 46, best seen by referring to FIG. 2, which serves to block the carriage 40 and thus the partition wall 22 in desired position.

Now according to a preferred embodiment of the inventive mixing apparatus a transmission rod 44 is rigidly connected to the upper edge of the body member or cylinder 24. Rod 44 is operatively connected with a suitable vibrator 50 attached to the outer wall 4 of the vessel or container 2, as shown. Vibrator 50 can be driven in any suitable manner, such as electrically or pneumatically, and is connected through the agency of a line or conduit 48 with any suitable energy source.

Elastic sealing lips or members 38 are carried at the edges of the partition walls 20 and 22 confronting the outer wall 4 of the container or vessel 2. According to the preferred physical manifestation of the invention the struts 36 are not rigidly connected with the cylinder or body member 24, rather the cylinder 24 is preferably provided with elastic bearing or support elements 42 which are secured to its wall and which undertake the support of the cylinder 24 at the struts 36.

Now for the purpose of furnishing the consumer or load 26 with a mixture of granular or pulverulent material composed of two material components and in a predetermined mixing ratio, the partition wall 22 is positionally adjusted with respect to the other partition wall 20 prior to the time that the apparatus is placed into operation such that the volume ratio of the storage compartments l0 and 12 correspond to the desired or predetermined mixing ratio of the materials. Thereafter, the storage compartments l0 and 12 are filled with the corresponding material components to be admixed, and in so doing material flows out of both storage compartments l0 and 12 through the ringshaped gap 8 into the collecting compartment or chamber 14. In other words material flows out of the storage compartments l0 and 12 in the form of sections of the material components corresponding to both of the storage compartments l0 and 12 and flows into the collecting compartment 14 and the latter, while having formed thereat an inverted or negative pouring cone of material fills up to such an extent that without removing material from the collecting compartment 14 no further material can flow out of each of both of the storage compartments 10 and 12. Since both material components are simultaneously filled into the corresponding storage compartments 10 and 12 these material compartments are also present in the collecting compartment 14 in a proportion by volume which corresponds to the desired mixing ratio. No appreciable mixing of the components occurs in the collecting compartment 14 prior to removal therefrom. After the collecting compartment 14 has filled while forming the previously mentioned pour cone 54 both of the storage compartments l0 and 12 can be completely filled. The fill of material in the storage compartment 12 has been depicted at the left side of FIG. 1 and indicated by reference character 52.

Assuming now that the consumer or load 26 requires a supply of mixed material, then by placing into operation the blower 28 a negative pressure condition prevails at the mixed material conduit 18. This negative pressure draws or sucks-in surrounding air through the upper open end of the air chute or shaft 30. Consequently, there is thus formed a conveying or transport air stream which wipingly moves past the surface or base of the pour cone 54 and thus entrains granular or pulverulent material out of the collecting compartment 14. By means of this conveying air stream such granular or pulverulent material is transported to the consumer or load 26 which it can be separated in the usual way, while the air is ejected at the pressure side of the blower 28, if desired, through the agency of a nonillustrated filter. Since the ratio of the cross-section of the sections of the ring-shaped gap 8 associated with both storage compartments l0 and 12, by virtue of the adjusted position of the partition wall 22 relative to the partition wall 20, corresponds to the volume ratio of both storage compartments l0 and 12 and therefore to the mixing ratio of both components of the materials to be admixed, and owing to the rotationally symmetrical construction and arrangement of the collecting compartment 14 with respect to the ring-shaped gap 8, the quantity of material components located in such collecting compartment 14 are present in a ratio corresponding to the desired mixing ratio. Accordingly, these material component quantities also are present in a proportion at the surface of the pour cone 54 which corresponds to the desired mixing ratio, and it will be recalled that the surface of the pour or filling cone 54 is subjected to the annular or ring-shaped air current flowing-in through the inlet opening 32. Consequently, this air current, during its entry into the mixed material conduit 16, likewise entrains a respective quantity of both material components which are always present in a certain predetermined and desired mixing ratio with regard to one another. Owing to the turbulence which prevails at the conveying or transport air stream these material components sufficiently admix with one another on their way to the consumer or load 26.

The after-filling of the materials to be mixed into both storage compartments and 12 can be controlled periodically or, if desired, as a function of the requirements of the consumer 26. Naturally, during operation a certain minimum filling level should be maintained in the storage compartments.

in the event there are processed material components which have poor flow characteristics then during such time as the blower 28 is placed into operation the vibrator 50 can also be placed into operation. Vibrator 50 then produces vibrations at the cylinder or body member 24. In this way there is facilitated passage of material through the annular or ring-shaped gap and the further flow of material out of the storage compartments is accelerated.

It is also possible to influence the mixing ratio which is determined by the spacing of the partition walls 20 and 22 from one another, especially in the case where the proportion of one component of the mixture is very small, in that the tube 16 which is then movably mounted is displaced out of its coaxial position, for instance in the sense of increasing the spacing from the storage compartment 10. Instead of carrying out an axially parallel displacement of the tube 16 such could also be rocked or pivoted in a manner such that its lower end is further removed from the storage compartment l0 and the associated ring-shaped gap section. In this way it is possible to achieve the phenomena that a relatively smaller proportion of material will be withdrawn or sucked-out of the storage compartment 10 than otherwise corresponds to the volume ratio of both storage compartments and the previously discussed mixing ratio.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

1. A method of admixing at least two fluent material components, especially pulverulent or granular materials, comprising the steps of sub-dividing the internal compartment of a material receiving container into at least two storage compartments having a volume ratio essentially corresponding to the desired mixing ratio of the material components, filling into each one of the storage compartments one of the material components which are to be admixed, withdrawing from the storage compartments the therein filled material components in a ratio corresponding to the desired mixing ratio of such material components and depositing such withdrawn materials at a collecting zone, generating a negative pressure condition at the region of the collected material components withdrawn from said storage, compartments, producing by means of such negative pressure condition a material conveying fluid medium stream over the surface of the collected material components to remove the components of the collected material in a ratio corresponding to the desired mixing ratio, and then transporting the thus withdrawn material components to a consumer while admixing such material components with one another during movement to such consumer.

2. The method as defined in claim 1, including the step of withdrawing the material components from the storage compartments and depositing such at the collecting zone without any appreciable admixing thereof.

3. The method as defined in claim 2, wherein the material components withdrawn from the storage compartments are collected in the collecting zone in the form of an inverted pouring cone having the base thereof uppermost in such collecting zone, and moving the conveying fluid medium stream over the surface of the base of such inverted pouring cone to withdraw the components of the collected material therefrom.

4. The method as defined in claim 1, including the step of replenishing the supply of the material components removed from the storage compartments.

5. The method as defined in claim 4, wherein replenishment of the supply of the material components is undertaken as a function of the requirements of the consumer.

6. The method as defined in claim 1, including the step of controlling the effect of the negative pressure acting upon the material components filled into the storage compartments to selectively vary and control the removal of such material components from each such storage compartment.

7. A mixing apparatus for the admixing of fluent materials, especially pulverulent or granular materials, comprising a container for the materials having an internal material receiving compartment, means for forming at said internal compartment of said container a substantially horizontally extending ring-shaped compartment which possesses a tapered cross-sectional configuration in the fall direction of the material and opens into a substantially ring-shaped gap, means for sub-dividing said ring-shaped compartment in its peripheral direction into at least two storage compartments, a material collecting compartment arranged beneath said ring-shaped compartment and communicating via said ring-shaped gap with both of said storage compartments, a mixed material conduit disposed to ascend out of said collecting compartment, and a substantially ring-shaped inlet opening for a material conveying medium disposed inwardly of said ring-shaped gap in the neighborhood thereof.

8. The mixing apparatus as defined in claim 7, wherein said container comprises a substantially rotationally symmetrical vessel having a vertically extending axis, said rotationally symmetrical vessel possessing an external wall which tapers downwardly, said external wall of said vessel forming at least a part of said ring-shaped compartment as well as the bottom of said collecting compartment.

9. The mixing apparatus as defined in claim 8, wherein said vessel possesses a substantially circular conical-shaped configuration, and wherein said means for sub-dividing the internal compartment of said vessel into a ring-shaped compartment incorporates a body member which forms the inner wall of said ring-shaped compartment.

10. The mixing apparatus as defined in claim 9, wherein the outer wall of said ring-shaped compartment is formed by the external wall of said vessel.

11. The mixing apparatus as defined in claim 10, wherein said body member is a cylinder.

12. The mixing apparatus as defined in claim 9, wherein said mixed material conduit comprises a tube arranged internally of said body member and together with said body member delimits said inlet opening for the conveying medium.

13. The mixing apparatus as defined in claim 12, wherein said tube is movably arranged within said body member.

14. The mixing apparatus as defined in claim 7, wherein said means for sub-dividing said ring-shaped compartment into at least two storage compartments comprises at least one pair of partition walls, and means for selectively displacing at least one of said partition walls in the peripheral direction.

15. The mixing apparatus as defined in claim 7, further including a blower having a suction side, means for placing in flow communication said mixed material conduit with said suction side of sajdjlower, and wherein said means for sub-dividing said internal compartment of said container into a ring-shaped compartment incorporates an air shaft for communicating said inlet opening with the surrounding atmosphere. 

1. A method of admixing at least two fluent material components, especially pulverulent or granular materials, comprising the steps of sub-dividing the internal compartment of a material receiving container into at least two storage compartments having a volume ratio essentially corresponding to the desired mixing ratio of the material components, filling into each one of the storage compartments one of the material components which are to be admixed, withdrawing from the storage compartments the therein filled material components in a ratio corresponding to the desired mixing ratio of such material components and depositing such withdrawn materials at a collecting zone, geneRating a negative pressure condition at the region of the collected material components withdrawn from said storage compartments, producing by means of such negative pressure condition a material conveying fluid medium stream over the surface of the collected material components to remove the components of the collected material in a ratio corresponding to the desired mixing ratio, and then transporting the thus withdrawn material components to a consumer while admixing such material components with one another during movement to such consumer.
 1. A method of admixing at least two fluent material components, especially pulverulent or granular materials, comprising the steps of sub-dividing the internal compartment of a material receiving container into at least two storage compartments having a volume ratio essentially corresponding to the desired mixing ratio of the material components, filling into each one of the storage compartments one of the material components which are to be admixed, withdrawing from the storage compartments the therein filled material components in a ratio corresponding to the desired mixing ratio of such material components and depositing such withdrawn materials at a collecting zone, geneRating a negative pressure condition at the region of the collected material components withdrawn from said storage compartments, producing by means of such negative pressure condition a material conveying fluid medium stream over the surface of the collected material components to remove the components of the collected material in a ratio corresponding to the desired mixing ratio, and then transporting the thus withdrawn material components to a consumer while admixing such material components with one another during movement to such consumer.
 2. The method as defined in claim 1, including the step of withdrawing the material components from the storage compartments and depositing such at the collecting zone without any appreciable admixing thereof.
 3. The method as defined in claim 2, wherein the material components withdrawn from the storage compartments are collected in the collecting zone in the form of an inverted pouring cone having the base thereof uppermost in such collecting zone, and moving the conveying fluid medium stream over the surface of the base of such inverted pouring cone to withdraw the components of the collected material therefrom.
 4. The method as defined in claim 1, including the step of replenishing the supply of the material components removed from the storage compartments.
 5. The method as defined in claim 4, wherein replenishment of the supply of the material components is undertaken as a function of the requirements of the consumer.
 6. The method as defined in claim 1, including the step of controlling the effect of the negative pressure acting upon the material components filled into the storage compartments to selectively vary and control the removal of such material components from each such storage compartment.
 7. A mixing apparatus for the admixing of fluent materials, especially pulverulent or granular materials, comprising a container for the materials having an internal material receiving compartment, means for forming at said internal compartment of said container a substantially horizontally extending ring-shaped compartment which possesses a tapered cross-sectional configuration in the fall direction of the material and opens into a substantially ring-shaped gap, means for sub-dividing said ring-shaped compartment in its peripheral direction into at least two storage compartments, a material collecting compartment arranged beneath said ring-shaped compartment and communicating via said ring-shaped gap with both of said storage compartments, a mixed material conduit disposed to ascend out of said collecting compartment, and a substantially ring-shaped inlet opening for a material conveying medium disposed inwardly of said ring-shaped gap in the neighborhood thereof.
 8. The mixing apparatus as defined in claim 7, wherein said container comprises a substantially rotationally symmetrical vessel having a vertically extending axis, said rotationally symmetrical vessel possessing an external wall which tapers downwardly, said external wall of said vessel forming at least a part of said ring-shaped compartment as well as the bottom of said collecting compartment.
 9. The mixing apparatus as defined in claim 8, wherein said vessel possesses a substantially circular conical-shaped configuration, and wherein said means for sub-dividing the internal compartment of said vessel into a ring-shaped compartment incorporates a body member which forms the inner wall of said ring-shaped compartment.
 10. The mixing apparatus as defined in claim 9, wherein the outer wall of said ring-shaped compartment is formed by the external wall of said vessel.
 11. The mixing apparatus as defined in claim 10, wherein said body member is a cylinder.
 12. The mixing apparatus as defined in claim 9, wherein said mixed material conduit comprises a tube arranged internally of said body member and together with said body member delimits said inlet opening for the conveying medium.
 13. The mixing apparatus as defined in claim 12, wherEin said tube is movably arranged within said body member.
 14. The mixing apparatus as defined in claim 7, wherein said means for sub-dividing said ring-shaped compartment into at least two storage compartments comprises at least one pair of partition walls, and means for selectively displacing at least one of said partition walls in the peripheral direction. 